Title

Author

Date of Award

Spring 2010

Document Type

Restricted Thesis: Campus only access

Degree Name

Bachelor of Science

Department

Chemistry

First Advisor

Dr. Michael Leopold

Second Advisor

Dr. Robert Miller

Abstract

Methods for controlling the polydispersity of monolayer protected gold nanoparticles (MPC) core sizes were investigated for the purpose of enhancing uniform protein adsorption at MPC modified electrodes, a condition that should result in nearly ideal protein monolayer electrochemistry (PME) at such interfaces. Fractionation and annealing procedures were implemented to separate crude (as-prepared), polydisperse MPC samples into more monodisperse samples. Differential pulse voltammetry (DPV) and TEM analysis with Image J generated histograms were applied to study the extent of monodispersity in the treated MPC samples by assessing the average core diameter and its deviation in the MPC sample. From these treated samples, MPC film assemblies on gold electrodes were constructed and PME was applied in order to study the monodispersity dependence of redox azurin protein at the MPC modified electrode. Specifically, the ability to approach ideality full width at half-maximum (fwhm) electrochemical values (90 mv) was studied. Comparison of both the determined average core sizes and fwhm values between as-prepared and treated MPC samples yielded no significance enhancement in monodispersity. DPV studies, however, confirmed that monodispersity was induced in ethanol soluble MPCs with average composition of Au140(C6)53. Overall, fractionation and annealing methods for controlling polydispersity of nanoparticles core sizes were not successful and thus the ideality of PME systems was not approached.